Kaimil_Saman_DBF AIAA OC Conference

8/10/2019 Kaimil_Saman_DBF AIAA OC Conference

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University of California, IrvineUCI Team Caddyshack


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The UCI AIAA student chapter participates in the annual AIAA Design

Build Fly (DBF) competition.

This competition gives the engineering students a chance to apply

classroom knowledge, gain hands on skills, and experience an

industry level project-development from conceptual design to

building and testing an optimized final product.

Over the past 6 years this project has grown substantially in size and

skill with the help of previous DBF students, currently working in the

aerospace industry, who meeting with the current team weekly.


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Introduction

Team Organization

2011 Competition

Conceptual Design

Preliminary Design

Detailed Design

Manufacturing

Testing

Expected Final Performance


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Project ManagerKamil Samaaan

Report

Lead: GiuseppeVenneri

Patrick Lavaveshkul

Semir Said

Westly Wu

Byron Frenkiel

CAD

Lead: PatrickLavaveshkul

Kerchia Chen

Sothea Sok

Angela Grayr

Erica Wang

Chief Engineer

Giuseppe Venneri

Aerodynamics

Lead: Curtis Beard

Rayomand Gundevia

Thuyhang Nguyen

Anthony Jordan

Max Daly

Propulsion

Lead: Kevin Anglim

Kasra Kakavand

Khizar Karwa

Alexander Mercado

Yi-lin Hsu

Structures

Lead: Hiro

Nakajima

Kurt Fortunato

Gagon Singh

Kevin Koesno

Michael Gamboa

Payload

Lead: Jacqueline

Thomas

Semir Said

Westly Wu

Stability andControl

Lead: David Martin

James Lewis

Giuseppe Venneri

Test FlightCoordinator

Alexander Mercado

Public Relations

Chen Weng


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Aerodynamics: Computes flight characteristics and necessary wing

dimensions.

Propulsion:Analyzes propulsion system to find best motor, propeller and

battery combination.

Structures: Optimizes load-bearing components and maintains a weights

build-up of the aircraft.

Payload:Designs and manufactures steel payload and restraints for the

payload and aircraft.

Stability & Control: Ensures aircraft meets S&C standards and works

closely with aerodynamics to predict flight performance.


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Competition consists of 3 missions:

Mission 1:Complete as many laps as possible in a 4-minutes. time

frame (M1 = Nlaps/Nmax)

Mission 2:3 laps with a steel bar payload.

(M2= 3x(Payload weight/Flight weight))

Mission 3:3 laps with

a team-selected

quantity of golf balls.

(M3 = 2x(Nballs/Nmax))


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Constraints for 2011:

Battery weight: lb

20 amp slow-blow fuse

Aircraft must fit in a commercially-available carry-on suitcase.

L + W + H = 45inches (no dimension can exceed 22 in.)

Suitcase must include entire flight system, including aircraft, battery and

all required parts and tools.

Golf balls are regulation sized and the steel bar payload dimensions are

constrained: 3 in. width x 4 in. length minimum.

Aircraft must be hand-launched.


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Sensitivity Analysis

Configuration Figures of Merit

Aircraft Configuration

Subsystems Selection

Motor Position

Landing Methods

Yaw Control

Wing Attachment Methods

Payload Configuration

Final Configuration


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The objective of this analysis is to identify the mission parameters

that have the largest impact on the score. A maximum of 64 golf balls and 9 laps were the benchmark values,

determined using the data from past DBF competitions.

Thrust and drag models were used in a simulation program to design

hundreds of planes and perform this analysis.

Mission 1 favors a small plane and

payload with a large propulsion

system.

Missions 2 and 3 favor a large

plane with a high wing loading.


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In order to select an aircraft configuration, a scoring system

based on figures of merit was produced. Each was weighted

based on results of the scoring analysis:

System weight (35%)

L/D (20%)

Cargo space (15%)

Maneuverability (10%)

Manufacturing (10%)

Hand launch (10%)


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Tractor- Lightweight, higher efficiency andless dangerous hand launch.

Pusher- greater lift due to lack of prop-

wash, limits the maximum amount of

sweep and a dangerous hand launch.

Double Tractor- Smaller propellers,

increased cargo space in center, less

dangerous hand launch, increased weight

and difficulty in locating the CG.

Push-Pull-Increased weight, limitsmaximum sweep and provides a more

dangerous hand launch.

FOMWeight

Single

Tractor

Single

Pusher

Double

Tractor

Push-Pull

System Weight 45 0 0 -1 -1

Drag 20 0 1 -1 0

Hand Launch 15 0 -2 1 -2

Stability 10 0 -1 0 -1

Cargo Space 10 0 1 2 -1

Total 100 0 -10 -30 -95


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Belly Landing-Low weight, low drag,

would be difficult to hand launch andvulnerable to fatigue.

Skid/ Handle-Improved hand launch,

increased structural support, potential

additional storage space and slight

increase in weight and drag.

Skid & Wire-Decreased stopping

distance, minor increase in weight and

increase in drag.

Tricycle-Reliable and high strength,

however significant increase in weight,

drag and difficulty of hand launch.

FOM Wt

Belly

Landing Handle/ Skid

Skid and

Piano wire Tricycle

System Weight 45 0 -1 -1 -2

Drag 20 0 0 -1 -2

Hand Launch 15 0 2 -1 -2

Stability 10 0 0 1 2

Cargo Space 10 0 2 0 0

Total 100 0 5 -70 -140


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Winglets-Reduced drag, lightweight and provides yaw stability.

Wingtip rudders- Increased pilot

control and increased weight.

Aft Vertical tail-Greater moment to

correct yaw and significant

increase in weight.

Split Flaps- Provides only a minor

increase in weight, complex and

difficult to implement correctly andcause and increase in drag.

FOMWeight Winglets

Wingtip

Rudders

Aft Vertical

Tail

Split

Flaps

System

Weight45 0 -1 -2 -1

Drag 25 0 0 -1 0

Hand Launch 15 0 0 -1 0

Stability 15 0 1 2 0

Total 100 0 -30 -100 -45


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Fully enclosed internal payload compartment-Less drag and a

lower weight. Requires a larger t/c airfoil or a larger aircraft.

Fuselage (BWB) style compartment-More efficient method of

cargo placement near the Center of Gravity, increased drag and

difficulty to manufacture.


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Design and Optimization Programs

Design Methodology

Mission Model

Aerodynamics

Airfoil Selection

Wing Sizing

Propulsion Sizing

Drag

Lift

Stability and Control

Mean Aerodynamic Chord

Winglets


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SolidWorks: used to model aircraft prototypes and to help determine

airfoil selection

XFOIL: Used to analyze possible airfoil choices for aerodynamiccharacteristics

Microsoft Excel: Used extensively for data analysis, storage andgraphing

AVL: Used for flight-dynamic analysis and to ensure overall stability

of the aircraft

MATLAB: Used to create an optimization program


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The mission profile was modeled using for loops and while loops in

MATLAB.

The aerodynamic and propulsion forces were computed for every loop-

iteration to determine the change in position and velocity of the aircraft

during that period of time.

The program assumed some initial conditions for takeoff such as handlaunch velocity and wind conditions.

The mission model program computes:

the energy used

the number of laps completed in 4 minutes

The maximum payload capacity a design could carry.

The total flight score is computed for several designs which resulted in

an optimized design.


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The majority of airfoils that were considered were the reflex type for our flying wing.

Studies were done using XFOIL and SolidWorks to determine which airfoil best suited

our needs.

Coefficient of moment vs. angle of attack NACA 4-digit symmetric series study


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Wing loading was optimized

based on the total flight score

using our mission profile MATLAB

program.

The figure to the right shows a

plot of the total drag as a function

of the aspect ratio for mission

three during takeoff.


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Battery Selection

Considered several different

battery types and the

capacity-to-weight ratios.

A mission profile was used to

determine an estimate of theamount of energy needed to

complete each of the

missions.Motor Selection

Based on the battery andthe current limitation of

20A, the maximum power

the battery could supply to

the motor is 300 W.

Propeller Selection

Pitch-High pitchperforms better at high

speeds while low pitch

performs better at low

speeds.

Diameter- Largerdiameter= more thrust

and more power

required from motor.

o Mission 1: High pitch

small diameter.

o Missions 2 & 3: Lower

pitch and larger

diameter.

Battery

Capacity mAh

Ah / oz

Redicom

500

1.56

Nimh

700 1.75

Elite 1500

1500 1.92Elite 1700

1700 1.7

Elite 2000

2000

1.72

Elite 2200

2200

1.44

Elite 3300

3300 1.71

Name Weight

oz

Kv

RP

M/V

Max

Current

Amp

Power

W

Resist

ance

Hacker

A30-14L

4.6

800

35

490

0.038

Hacker

A30-12L

4.6

100

0

32

400

0.041

Hacker

A30-10L

4.8

118

5

35

450

0.023

HackerA30-8XL

5.5

110

0

35

600

0.015


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The drag was computed using the equivalent flat plate area method.


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The wing was optimized

for the cruise of mission

two and three.

Washout helped focus

the peak of the CL

distribution.


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We calculated our MAC and

simulated our aircrafts geometry

through AVL

The figure to the right shows the

resulting pole-zero map of the

eigenvalues calculated by theprogram.


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WINGLETS

An eignemode analysis made in AVLshowed that the flying wing was susceptible

to low Dutch roll damping.

Dutch roll was clearly visible during test

flights, but Pilot still maintained good control.

Sized for Dutch roll damping above 0.02.

Optimized Winglet Dimensions

Height c/4: 9.5 in

Sweep: 37 degreesDistance behind LE: 6.0 in

Taper ratio: 0.7


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We modeled the wing sparas an I-beam.

Carbon strips were laid on

the top and bottom of the

wing with a 5/8 diameter

carbon rod running between

the strips to create our spar.

Testing later on showed that

the wing with two spars was

favored over the single spar.


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In an effort to reduce weight, the motor mount, landing skids and launch

handle were combined into one carbon fiber structure that was

integrated into the center wing section.

This design proved to be very efficient in cargo space utilization.

The forward end is used as an electronics compartment to house the

speed controller and the fuse.

The skid and handle section was designed as a channel that was sized to

fit the propulsion battery pack.


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Foam wings were

created and hollowed

out using wooden

templates and a hotwire

as investigated over

summer.

Wings were then coated

with fiber glass and a

strip of carbon fiber for

strength.


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Wingtip Testing

Propulsion Testing

Handle Design Tests

Flight Tests


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Wing tip testing was used to confirm and validate wing-sparcalculations and our hollow core foam design.

Testing was performed

by securing the tips

of a wing and loading

it mid-span until

failure occurred.


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Static thrust testing was conducted to measure the performance of various

propulsion systems.

Dynamic thrust testing was conducted using a load cell that was mounted to a

custom-designed sliding motor mount and was used to collect dynamic thrust

data during flight.

This data was used to accurately model the dynamic thrust in the mission profile

optimization program. Fuse and battery testing were also conducted in the lab to determine the limits

and range of operation.


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Different handle designs were

created and tested initially to

find which best suited the hand

launcher to give him control

and stability at take off.


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The following are a combination of both

prototypes, and were used to calibrate the

preliminary design.

Takeoff speed: 30 ft/s

Max wing loading: 28 oz

Locating CG for stable flight: 15% static

margin

Dutch roll damping: Controllable

Lap time: 37 s

Prototype I

Prototype II


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Prototype I

Provided insight into launch and landing techniques.

Provided data for the calibration of the wing loading.

Prototype II

Improved stability.

Increased payload space.


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The conditions surrounding the fuse inTucson are very different than those in Irvine.The fuse will blow at a lower current inTucson.

Flying later in the day helped with the abovehandicap, when it was cooler. In fact, heavyplanes like those from Israel and MIT skippedtheir noon rotation and waited till the lateafternoon to fly their airplanes (9 lbs!!).

Conduct propulsion tests and test flights withcompetition weather conditions in mind.

Documents

Kaimil_Saman_DBF AIAA OC Conference